In deep sea sport fishing a downrigger apparatus is used to maintain a fishing line at a selected fishing depth beneath the surface of game fish inhabited water. The downrigger apparatus is fixed to the boat. It includes a large reel usually connected to a boom and a supply of stainless steel downrigger cable spooled on the reel. The cable extends from the reel and is trained over the boom tip and into the water. The free end of the cable extends to a depth which is a function of the selected fishing depth in that it will be a depth greater than the selected fishing depth. A trolling weight is attached to the end of the cable in the water. The reel can be manually or electrically operated. Conventional fishing tackle is used along with the downrigger apparatus. A fishing rod line is releasably attached to the downrigger cable by means of a release clip at approximately the selected fishing depth in the water. The release clip secures a segment of the fishing line at the desired depth. During trolling, the fishing line descends generally vertically to the release clip, and then rearward from the release clip. A lure attached to the end of the fishing line is maintained at about the selected depth and trails horizontally. Upon the abrupt impact of a fish striking the lure, the release clip releases the fishing line from the downrigger cable. The fish is then conventionally landed with the fishing tackle.
A typical deep sea fishing depth might be 150 feet to 200 feet. At that depth there is little or no light from the sea surface whereby the lure is not as visually apparent to the fish as it is at a lesser depth. At such a depth, the fish is more apt to perceive sound before it perceives the visual attraction of a fishing lure. Sound waves are readily transmitted through the water. Game fish have a sensitive ear enabling them to hear sounds transmitted through the water. Additionally, fish have lateral line organs that enable them to sense sound wave vibration in the water. The fish are apt to associate the sound with a prey in distress and be attracted to the source.